Abstract [en]

Although cognitive radio networks (CRNs) were originally intended as a powerful solution to enhance spectrum utilization, it can also be used to improve reliability by avoiding interference in the 2.4 or 5 GHz band. Using multiple relay nodes in CRNs, the outage probability, i.e., the probability that the end-to-end signal-to-noise ratio drops below a predefined threshold, can be reduced significantly. This implies that the probability that a message is not delivered within a specific time frame, can be kept below a required threshold, even when there are constraints on energy efficiency in terms of peak transmit power. This is particularly useful for industrial networks with realtime constraints. However, using CRNs may also reveal secret information to eavesdroppers (EAVs). Therefore, guaranteeing secure and reliable communications in CRNs is still a challenging problem. To this end, the secrecy performance of a proactive decode-and-forward relaying scheme in a cognitive cooperative radio network is investigated. More specifically, analytical as well as approximate expressions for the secrecy outage probability and probability of non-zero secrecy capacity are derived to evaluate the system performance. Numerical results show that the approximation tightly match the analytical results and simulations, and thus it can be used to provide a fast evaluation of the security and reliability of communications using a considered assignment of relay nodes in a cognitive cooperative radio network (CCRN). Consequently, our results enable to secure the communication, and increasing the reliability, availability, robustness, and maintainability of wireless industrial network, subject to various constraints from the CRN.